A static helper library that provides NMPlatform and other utils.
This is NetworkManager's internal netlink library, but also contains
helpers for sysfs, ethtool and other kernel APIs.
NMPlaform is also a cache of objects of the netlink API: NMPCache
and NMPObject. These objects are used throughout NetworkManager
also for generally tracking information about these types. For example,
NMPlatformIP4Address (the public part of a certain type of NMPObject)
is not only used to track platform addresses from netlink in the cache,
but to track information about IPv4 addresses in general.